As semiconductor technology develops, metal-oxide-semiconductor (MOS) devices have been the basic logic building blocks for integrated circuits. In addition, various passive components, such as resistor devices, capacitor devices and inductor devices, may be formed on the same semiconductor wafer with the MOS devices. In traditional MOS processes, after a source/drain (S/D) implant operation is performed, a deposition process is performed to form an oxide layer to cover the semiconductor wafer, and a photolithography process and an etching process are sequentially performed on the oxide layer to form resistor protect oxide (RPO) layers of the resistor devices.
However, while existing methods for manufacturing semiconductor devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.